Magnetic couplings



Nov. 6, 1956 1. v. ZozuLlN ET AL MAGNETIC COUPLINGS Filed March l5, 1954 /NYENTORS /GOR V.

ZOZ UL/N GEORGE J. OKUL/TCH GEORGE M. VOL K OFF VLADlM/R d- OH UL l TCH ALE s. d. ELLETT ATTORNE Y United States Patent O 2,769,932 MAGNETIC COUPLIN GS Igor V. Zozulin, vGeorge J. Okulitch, George M. Volkotf, Vladimir I. Okulitch, and Alec S. J. Ellett, Vancouver, British Columbia, Canada, assignors, by mesne assignments, to Tormag Transmissions Limited, Vancouver, British Columbia, Canada Application March 15, 19,54, Serial No. 416,324 Claims. (Cl. 310-105) Our invention relates couplings.

The objects of the invention are to provide a compact eddy current type lcoupling using permanent magnets which is capable of transmitting industrial amounts of torque and or power within a range of 10 horsepower at 1800 revolutions per minute; to realize a predetermined slip-torque characteristic by which high efficiency can be combined with overload and stalling protection; to provide a structure whereby the full output of the motor normally driving the coupling will be converted into heat in the coupling in the event of indefinite stalling without damage to the coupling; to provide a disposition of the predominant heat producing element of the bimetallic plate surrounding the magnetic rotor close to the eX- ternal surfaces of the coupling, and to provide for adequate air iiow past said element to prevent undue expansion and distortion radially, so that the desired narrow air gap between magnets and bimetallic rotor may be maintained and that the torque under stalled conditions does not drop as the coupling is heated, and to provide a totally enclosed structure for the magnetic rotor to prevent contamination.

Referring to the accompanying drawings:

Figure 1 is a longitudinal sectional View of the invention.

Figure 2 is an extended fractional plan View of the copper band of the bimetallic rim showing the relative disposition of the rivets and their relation to the magnets of the rotor.

Figure 3 is a detail sectional view of washer or lock ring, taken on the line 3`3 of Figure 1.

Figure 4 is `a part elevational view of the coupling earrier plate or front of the housing.

In the drawings like characters of reference indicate corresponding parts in each figure.

The numeral 1 indicates an electric motor having a drive shaft 2. Fitted upon the shaft 2 is a hollow hub 4 which is slotted at its inner end as at 5 to permit circumferential contraction of the hub onto the inner end of the shaft. A key 6 is used to secure the hub 5 to the drive shaft.

The hub 4 is flanged as at 8 and of bearings 9 which to improvements in magnetic the clamping is fitted with a pair support the hub 2,769,932 Patented Nov. 6, 1956 The inner end of the steel band 32 is fitted with an internal annular flange 37 which in cross section is substantially similar to the outer peripheral portion 38 of end plate 28. The flange 37, the bimetallic rotor 31 and the peripheral flange portion 38 form a housing 40 for the magnetic rotor 11 and serve to outer faces and vanes 47 on their inner faces and are also provided with circumferentially disposed vent orifices 48 intimate contact with the steel band 31. arrangement of the rivets 3S and the dilation grooves erated in the copper element thereof.

The boss 29 of the end plate 28 is drilled and threaded as at 50 to receive a bolt for the purpose of removing said end plate from the coupling.

thus enabling high ina good path for the magnetic ilux,

transmission to be dustrial 'amounts of torque and power realized.

What We claim as our invention is.:

1. A slip torque coupling comprising a unit'having a drive rotor and a driven rotor, said drive rotor having a hub projecting to one side of said unit and adapted to be fitted to the shaft of a motor, a hub sleeve journalled on said hub, an annular rim supported in widely spaced relation from said hub sleeve, said rim being tted with a row of circumferentially spaced magnets, a ange supported from the outer end of Said hub, said ange having a bimetallic cylindrical band in close proximity to the pole pieces of the magnets, one edge of said bimetallic cylindrical band being fitted with an internal ange, said internal flange and a substantially similar portion of the rst named flange forming with the cylindrical band and the magnet carrying rim a housing enclosing the row of magnets, said bimetallic band consisting of an outer element of magnetic material and an inner element of nonmagnetic material, said inner element being attached to the outer element by a zig zag row of rivets, al1 of said rivets being a substantial distance from the edges of the band.

2. A slip torque coupling as claimed in claim 1, Wherein no two of said rivets are placed on a line extending parallel to the axis of the bimetallic band.

3. A slip torque coupling. as claimed in claim 1, wherein the inner lamination of the bimetallic band is spaced from the inner and outer flanges to dene dilation grooves.

4. A slip torque coupling as claimed in claim l wherein the rivets areat least one more in number than the number of magnets ina single row.

5. A slip torque coupling as claimed in claim l wherein the rivets are at least one less in number than the number of magnets in a single row. v

References Cited in the le of this patent UNITED STATES PATENTS 643,413 Kennedy Feb. 13, 1900 1,988,922 Stevenson Ian. 22, 1935 2,259,311 Kilgore Oct. 14, 1941 2,396,000 Findley Mar. 5, 1946 2,479,989 Winther Aug. 23, 1949 FOREIGN PATENTS 586,576 Great Britain Mar. 24, 1947 985,737 France L-:II: Mar. 14, 1951 

